Blacklisting (Updated 14-Mar-03)

Blacklisting - when a modem won't dial particular
number(s).

Blacklisting is country specific: telecommunications
regulations vary from country to country across the world, and a number of
countries have regulations limiting the number of times you can legally call the
same busy number in a specific period of time.

When blacklisting becomes active, attempts to
dial out will fail - various modems may respond differently. Some may respond
with a blacklisted or delayed message. After the country-defined
time has elapsed, dialing will again work.

There are several methods that can be used to
work around blacklisting:

Select a country for modem installation/dialing
that does not require blacklisting (U.S. is one); however, depending upon your
country's telephony standards, the modem may not properly dial, recognize
dial-tone, ring and/or busy, although it may be possible to dial blind -
(add x1 to extra settings).

Change the date/time in Windows to a later
date/time. (Double-click the time in Windows' System Tray to change the time.)

Some ISPs may have more than one phone number
that can be used to reach the same modem bank - change the last digit of the
phone number and check to see if your ISP answers with a modem.

Use a modem-specific command that disables or
modifies blacklisting:

Rockwell/Conexant modems - you may be able to
disable blacklisting with the command: (AT) %TCBAT*D - displays delayed numbers; AT*B - displays
blacklisted numbers.
If %TCB works, it may be added to the modem
initialization string.

Another trick that may work: if you use a
different number as the number to dial, the modem may treat it as a different
number for blacklisting, even though the call is routed to the same number. For
example, if the ISP phone number is 555-5555, and your phone company
allows codes like *## to enable or disable calling features, you could
use: